Arrangement for contouring tubes



March 15, 1966 SELLARS ETAL 3,240,045

ARRANGEMENT FOR CONTOURING TUBES 5 Sheets-Sheet 1 Filed Oct. 15, 1962 INVENTORJ D D. SELLARS THORNESS ZZZ ATTORNEY March 1966 L. D. SELLARS ETAL 3,240,045

ARRANGEMENT FOR GONTOURING TUBES Filed OCT. 15, 1962 5 Sheets-Sheet 2 4 35 3| FIG.5

' I 59 il/[W 46 i i INVENTORS LEONARD 0. SELLARS BEN M. THORNESS BY 1 2 i-+ V 2 FIG. 3

AT T0 RNEY March 15, 1966 L D. SELLARS ETAL 3,240,045

ARRANGEMENT FOR CONTOURING TUBES Filed Oct 15, 1962 5 Sheets-Sheet 3 LEONARD o. fL BEN M. THORNESS WZQZZ ATTORNEY United States Patent M 3,24l),045 ARRANGEMENT FOR CONTOURING TUBES Leonard D. Seliars, Rolling Hills, and Ben M. Thor-tress, Inglewood, Calif., assignors to Precision Sheet Metal, Inc, Los Angeles, Calif-Z, a corporation of California Filed Oct. 15, 1962, Ser. No. 230,320 14 Claims. (Cl. 72-405) This invention pertains to tube forming, and in particular to imparting a taper to a tube.

Frequently it becomes necessary to taper tubes at various portions or throughout their lengths. One use for such tubes is in the construction of rocket motors. There it may be required to assemble a large number of the tubes around the periphery of the motor with each of the tubes being tapered throughout its length. Frequently the tubes are of varying contour, having a relatively small diameter at some portions, while others are enlarged. Tolerances are extremely exacting for such work, and each tube must be given a precise dimension. Generally, a constant wall thickness is specified regardless of the outside diameter given the tube. The materials involved in tube tapering frequently are those that are particularly difiicult to form, such as the harder stainless steel alloys on one hand or metals that are very soft on the other.

In the past it has been proposed to provide a pair of opposed dies having tapered grooves that together define an opening through which the tube is passed to reduce its dimension. This means that rotation of the dies will vary the opening that they provide. As the tube is forced through the dies, a tension force may be applied to the tube, and it is rotated during this time as well. It has been the belief in the past that the dies should not entirely circumscribe the tube, but that each groove should extend through an arc of only around 150. This arises from the fact that the groove edges tend to dig into the tube as it initially contacts the die grooves while approaching the central aperture defined by the dies. This has resulted in the practice of providing a generous convex radius at the groove edges to prevent damage to the tube. Furthermore, the two opposed dies contact the tube at laterally spaced positions as the tube moves into the dies, which compresses the tube from two sides and may cause a flattening of the tube. Therefore, while this technique has suitably formed tubes in a number of instances, the scrappage rate has been high and it has been difiicult to impart extreme tapers to the tubes. In many cases galling of the surface of the tube occurs.

The present invention provides an improved tube contouring arrangement permitting tubes to be tapered in almost any degree. The number of improperly formed tubes is drastically reduced, and the tube surfaces are smooth without galling or other imperfections. Hence production rates are increased and costs are reduced. This is accomplished by means of a die arrangement that includes four rollers rather than two as in prior designs. Each of the rollers includes a tapered groove, and together they define an opening through which the tube is passed. Each groove has an arc transversely of virtually 90 so that together they completely encircle and contact the periphery of the tube. By engaging the tube throughout its circumference the contouring of the tube is materially improved as the tube passes through the die opening. This complete contact of the tube becomes possible only through the use of four rollers that engage the tube at a favorable draw angle as it approaches the die aperture, and contact the tube in a manner such that the groove edges do not tend to gouge the tube surface. By contacting the tube on four sides, the dies confine the tube rather than flattening it as it enters the dies.

In imparting a taper, the rollers are turned in synchronism to vary the opening. This is accomplished by means 3,24%,h45 Patented Mar. 15, 19636 of a gear system that includes a bevel gear carried by each of the rollers. A single ring gear rotates these bevel gears equally and simultaneously. An additional ring gear is carried by the first ring gear, and in turn is rotated by a rack. Movement of the rack is controlled by the cylinder of a tracer system operating on a template. The tube is rotated as it passes through the dies, and a tension force is applied to it at this time. The template and tracer system gives appropriate movement to the rack, which through the gear train turns the rollers causing them to vary the diameter of the opening around the tube. Superimposed upon this movement of the rollers, and continually present during the movement of the tube, is an oscillatory motion by which the rollers are rotated back and forth very slightly during the forming operation. Although this movement is relatively small it improves the ability of the rollers to form the tube causing them to swage the tube slightly as it passes therethrough. In addition, it facilitates lubrication of the tube as it is engaged by the rollers. The result is that the tubes may be rapidly formed to extreme tapers and within close tolerances.

Therefore, it is an object of this invention to provide an improved arrangement for imparting a taper to a tube.

Another object of this invention is to engage a tube throughout its periphery while reducing the: diameter of it.

A further object of this invention is to provide an arrangement for forming tubes to extreme tapers and close tolerances.

Yet another object of this invention is to reduce the diameter of tubes without impairing their surface finish or tending to flatten or otherwise distort the tubes during the forming process.

These and other objects will become apparent from the following detailed description taken in connection with the accompanying drawing in which:

FIG. 1 is a side elevational view of the tube contouring machine of this invention,

FIG. 2 is a top plan of the arrangement of FIG. 1,

FIG. 3 is an enlarged transverse elevational view of the movable carriage illustrating the rollers used in tapering a tube.

FIG. 4 is a sectional view taken along line 44 of FIG. 3,

FIG. 5 is a perspective view of one of the rollers showing the tapered groove at its end,

FIG. 6 is a fragmentary elevational view illustrating the roller bevel gear meshing with the adjustment drive gear,

FIG. 7 is a fragmentary sectional view taken along line 7-7 of FIG. 3 illustrating the adjustable eccentric for varying the stroke of oscillation of the rack, and

FIG. 8 is an enlarged fragmentary sectional view of the eccentric adjustment showing the parts in a different position for reducing the stroke.

With reference to the drawing, as seen in FIGS. 1 and 2 the arrangement of this invention includes a machine having a stationary bed 1 provided with longitudinally extending ways 2. A carriage 4 is movable along the path defined by the ways, powered by any suitable arrangement such as feed screw 5. On opposite sides of carriage 4, chucks 6 and 7 are supported in an axially aligned relationship on shafts 8 and 9. Chuck 6 is rotatable by means of a motor 10 which drives the shaft 8. The other chuck 7 is rotated equally and simultaneously by the motor. To this end the shaft 8 carries a pinion 11 driving a gear 12 which in turn rotates a shaft 13. At the opposite end of shaft 13 is a gear 14 identical to the gear 12 which drives gear 15 on the shaft 9. The latter gear is similar to gear 11 so that the chucks are coupled and rotate together.

In addition, there is a provision for imparting axial movement to the chuck 7. As seen in FIGS. 1 and 2 the shaft 9 includes axially extending spline 17 that slidably extends through the gear 9, mating with a comparable recess in that element. The gear 9 is restrained by bearings l8 and 19 and hence remains axially fixed. A thrust bearing 21 is carried at the end of shaft 9 and received within a connector 22 where it is held between wall 23 and flange 24. The connector 22 is carried by the distal end of a piston rod 26 that extends into hydraulic cylinder 27. It can be seen, therefore, that by extension or retraction of the rod 26, the chuck 7 can be caused to move toward or away from the chuck 6. This splined connection of shaft 9 to the gear permits the gear to float on the shaft 9 as this movement takes place.

With particular reference now to FIGS. 3 and 4 the lower portion of the movable carriage 4 includes a housing 30 that carries a cluster of four rollers 31, 32, 33 and 34. These rollers are all the same and are mounted in the housing 3t) so that their inner edges are in juxtaposition. Hence, the radial end wall 35 of roller 31 is adjacent the circumferential surface of the roller 32. Similarly, the radial end wall 36 of roller 32 is alongside the outer surface of roller 33, while the end wall 37 of the latter roller extends to the circumference of roller 34. The end wall 38 of roller 34 is alongside the circumferential surface of roller 31.

Each of the rollers is provided with a tapered recess arcuate in cross section at the juncture between its end wall and the circumferential wall. This construction is shown in FIG. as well as FIGS. 3 and 4. These recessed grooves 40, 41, 42 and 43 cooperate to define a circular opening 44 which is axially aligned with chucks 6 and 7. It is through this opening that the tube passes when it is being tapered in accordance with this invention.

It can be seen by the foregoing, therefore, that the rollers are not mounted in an opposed relationship. Instead, they are offset so that their inner corners join. They are arranged, however, so that the axis of each roller is perpendicular to the axis of the adjoining roller. The tapered grooves provided at the ends of the rollers together define substantially an entire circle. In other words, the rollers are quite closely fitted together and each groove extends through an arc of approximately 90. Thus a tube passing through the opening 44 will have contact with the four rollers about virtually its entire periphery.

In order to vary the dimension of the opening 44 the rollers are turned equally and simultaneously to bring different portions of the tapered recesses 40, 41, 42 and 43 into operative position. Such movement is effected by a gear drive arrangement. Hence, the rollers are connected to bevel gears 45, 46, 47 and 48. These gears are coaxial with the rollers with which they are associated, connecting to the rollers through shafts 49, 50, 51 and 52. As seen in FIG. 4 there is a screw 53 extending through the gear shaft and roller holding these elements together. A pin 54 projecting from the shaft enters a complementary recess in the roller, coupling the shaft and roller. Tapered roller bearings 55 and 56 mount the shaft in the housing 30.

A larger ring gear 58, coaxial with the opening 44 engages all of the smaller bevel gears of the rollers. In view of the offset relationship of the rollers the gear 53 is somewhat similar to a hypoid gear being arranged so that its teeth are not radial and hence a projection of the teeth will not intersect the gear axis.

On the opposite side of gear 58 and coaxial with it is a ring spur gear 59 that meshes with a vertically positioned rack 60. The gear 59 rotates with gear 58 and may be formed as part of the same piece of material, or more practically may be a separate member fastened to gear 53.

The upper end of rack 60 is connected by pin 61 to a rocker arm 62. One end of arm 62 is connected by transverse pivot pin 63 to a substantially U-shaped frame 64. On the opposite end of rack 60, pin 65 connects the arm to a link 66.

A cross shaft 67, which is parallel to the pins 61, 63

4- and 65, mounts the upper end of the link 66. This is a rotatable shaft being driven by a pulley 68. Belt 69 extends to a motor 7 t for turning the pulley 68.

The purpose of rotation of shaft 67 is to impart a vertical oscillatory movement to the outer end of the beam 62. Therefore, the shaft 67 includes an integral eccentric portion 71, which is received in an eccentric collar 72. The latter member is received in a bearing 73 in link 66. An extension 74 projects from eccentric collar 72 to the exterior of link 66 to permit adjustment of the collar, which may be locked to the shaft by set screw 74. This allows the eccentrics of the collar and shaft to be on the same side, to be on opposite sides or at any relative rotational position in between. In this manner the amount of pivotal movement of the rocker arm 62 is controlled. If the two eccentric parts are relatively positioned as shown in FIG. 4 where they are adjacent, a maximum stroke will be imparted to the link 66 and hence to the arm 62 as the shaft and collar rotate. Adjustment to a different rotational position, however, as seen for example in FIG. 8, reduces the amount of movement imparted to the link 66 and decreases the amount of oscillation that the link 62 receives.

A horizontal plate 75 extends across the upper portion of the framework 64. This plate is connected to the end '76 of a piston rod projecting from hydraulic cylinder 77. The cylinder is vertically fixed with respect to the carriage 4, being supported by an upward extension 78 of the housing 30. The cylinder 77 is the power output device of a tracer system whereb the axial position of the rod '76 is governed by the contour of a template. The tracer system may be of generally conventional nature including a follower 79 extending from tracer valve 80 that controls the movement of the cylinder. A template 81 is carried by the machine extending horizontally generally between the chucks 6 and 7.

It can be seen, therefore, that the plates 75 will be given a vertical movement as the carriage 4 travels along the ways 2, which movement is governed by the contour of the template 81. This movement in turn is imparted to the arm 62 through the connection at pin 63 and link 66. This causes the rack 60 to be raised or lowered, which through the gears 58 and 59 and the smaller bevel gears causes the rollers to turn: In this manner the size of opening 44 is controlled through the tracer system and the gear drive.

Superimposed on this movement is an oscillation vertically of the rack 60 as effected by the rotation of pulley 68 and the shaft 67. In other words, while the overall vertical position of the rack 6b is controlled by the trace unit, a continuous reciprocation is imparted to the rack by the movement of rocker arm 62. The reciprocative stroke of the rack is relatively small and may be controlled by appropriate positioning of the eccentrics at the link 66.

In forming tubes in accordance with the teachings of this invention, therefore, the carriage 4 is positioned at one end of the machine and the tube 82 is secured in the chucks 6 and 7. By means of the hydraulic cylinder 27 a tension is imparted to the tube which will vary with the material and size of the tube involved. Generally, however, the tube will be stressed to just below its yield point. Then with the tube rotating the carriage is advanced along the ways 2 causing the tube to pass through the opening 44.

As the tube 82 moves through the rollers it is bathed with a lubricant discharged from opening 83. The lubricant thus enters a chamber 84 at the entrance to the rollers Where it is confined by a flexible wall 85 secured to the housing. This causes the tube to pass through a pool of lubricant so that all portions of its exterior are covered as it enters the dies.

The size of the opening 44 depends upon the particular template contour, and hence the relatively rotational position of the rollers. In addition, the rollers are given a very slight reciprocative rotation through the pivotal movement of the rocker arm 62. Therefore, as the tube passes through the opening 44 there is a swaging action from the movement of the rollers as they are repeatedly forced against the exterior of the tube. This may be a relatively gentle action as the oscillatory movement need not be rapid and may travel through a short stroke. Generally, the rack will be given movement somewhere in the range of from 0.0001 to 0.010 inch. The frequency will be normally from three hundred to five hundred strokes per minute.

The four roller arrangement of this invention offers distinct advantages over prior designs, enabling tubes to be formed faster, more accurately and to more extreme tapers than previously possible. The entrance to the rollers presents four outwardly flaring concave surfaces which gradually become smaller as they converge to the central aperture through which the tube passes. This contour provides a favorable draw angle as the tube is reduced in dimension. By being confined on four sides, the tube will not tend to be flattened as it enters the rollers and is reduced in diameter. The four grooves of the rollers contact the tube at angles such that each groove may extend transversely through an arc of almost 90. This is possible because the edges of the grooves will not tend to dig into the tube surface, due to the angle of contact at the grooves. This permits the grooves to define an opening 44 at the center, where the tube is engaged for substantially 360. The full contact of the tube assures improved contouring of it.

This contrasts markedly with the older use of two rollers with tapered grooves. There the angle of contact as the tube enters the confined opening of the dies is relatively poor. The edges of the two grooves tend to dig into and cut the surface of the tube as they come in contact with it. For this reason a radius is needed at the groove edges, which means that the dies cannot contact the tube for a full 360 are as the tube passes through. Also, by compressing the tube from two sides with a gap in between as the tube enters the dies, the rollers frequently flatten and distort the tube.

Moreover, the small oscillation that the rollers receive helps to swage the tube to its new size rather than depending merely upon drawing the tube through a die opening. This reciprocative movement also facilitates lubrication of the tube as it passes through the aperture defined by the rollers. The swaging action can be used to improve the results obtained with prior designs Where only two die members are used.

The foregoing detailed description is to be clearly understood as given by Way of illustration and example only, the spirit and scope of this invention being limited solely by the appended claims.

We claim:

1. An arrangement for tapering tubes comprising a cluster of four substantially identical rollers,

each roller having a circumferential side wall connecting to a radial end wall,

said rollers being positioned with the radial end of each in juxtaposition with the circumferential wall of the adjacent roller and the axes of such adjacent rollers perpendicular to each other, the axes of said rollers being fixed,

each roller having a recess in the peripheral edge at the connection of said side wall to said end wall,

said recesses being in adjacency for thereby defining a central opening through said cluster of rollers,

and means for passing a tube through said opening for conforming said tube to the contour of said opening.

2. A device as recited in claim 1 including in addition means for imparting a relatively small oscillatory rotation to said rollers about the axes of said rollers while a tube is passing therethrough.

3. A device as recited in claim 1 in which each of said recesses is elongated and tapered in cross section from one end to the other,

and including means for equally and simultaneously adjusting the rotational positions of said rollers for thereby controlling the size of said central opening. 4. An arrangement for tapering tubes comprising a cluster of four substantially identical rollers,

each roller having a circumferential side wall con necting to a radial end wall, said rollers being positioned with the radial end of each in juxtaposition with the circumferential Wall of the adjacent roller and the axes of such adjacent rollers perpendicular to each other, each roller having a recess in the peripheral edge at the connection of said side wall to said end wall, said recesses being tapered in cross sectional dimension from one end to the other, said recesses being in adjacency for thereby defining a central opening through said cluster of rollers, means for extending a tube through said opening and supporting it on either side of said rollers, means for rotating such a tube, means for applying a tension force on such a tube, means for effecting relative movement of said tube and said rollers axially of said tube and said opening in a direction such that said recesses taper toward said opening in the direction of said movement, and means for equally and simultaneously rotationally positioning said rollers for cont-rolling the size of said opening. 5. A device for contouring a tube comprising die means having a plurality of rotatable elements,

said rotatable elements having cooperative recesses therein which together define an aperture having a contour to be imparted to :a tube, said recesses being of varying dimension whereby upon rotation of said rotatable elements the size of said aperture is controlled, means for simultaneously supporting, rotating and applying a tension force to a tube extending through said aperture, means for accomplishing relative movement of said rotatab'le elements and said tube for thereby progressively passing said tube through said aperture, means for positioning said rotatable elements in predetermined rotational relationship during such relative movement for thereby controlling the size of said aperture, and means for superimposing a relatively small amount of oscillatory rotational movement on said rotatable elements for providing a swaging action on a tube passing through said aperture. 6. An arrangement for tapering tubes comprising a cluster of four rollers,

each of said rollers having a radial end wall and a circumferential side wall, said walls meeting at a peripheral edge, said edges of said rollers being arranged in juxtaposition with each other, said rollers being positioned with each of said radial end walls in juxtaposition with the circumferential Wall of the adjacent roller,

said peripheral edges being provided with arcuate recesses therein so that said rollers together decline an aperture for receiving a tube, means for supporting a tube so as to extend through said aperture, means for rotating the tube so supported, means for simultaneously with said rotation applying a tension force to said tube, and means for causing relative movement of said tube and said cluster of rollers axially with respect to said aperture and said tube,

whereby said tube is brought through said aperture for thereby forming said tube.

7. A device as recited in claim 6 in which each of said recesses is arcuate in cross section, extending arcuately through substantially 90.

8. A device as recited in claim 6 in which each of said recesses is arcuate in cross section through substantially 90, and each of said recesses is of varying cross section lengthwise thereof.

9. A tube forming machine comprising a carriage,

a cluster of four rollers carried by said carriage,

each of said rollers having a radial end wall connecting at a peripheral edge to a circumferential side wall, said rollers being positioned with said edges in juxtaposition with each other, the end wall of each roller being in juxtaposition with the circumferential wall of the next adjoining roller, said edge of each of said rollers including an elongated recess therein of progressively larger dimension from one end to the other, each of said recesses being arcuate in cross section and extending transversely substantially 90,

whereby said recesses collectively define a circular aperture adapted to receive a tube, means for imparting an oscillatory movement to said rollers,

tubes supporting means on either side of said aperture for supporting a tube extending through said aperture,

said means including means for rotating said tube at either end thereof,

means for imparting a tension force to said tube during such rotation,

means for causing relative movement of said carriage and said tube for thereby progressively passing said tube through said aperture,

means for simultaneously rotating said rollers for controlling the size cf said aperture,

and means for controlling said simultaneous rotation of said rollers for varying the dimension of said aperture predeterminately as said relative movement takes place.

10. A device as recited in claim 9 in which said means for simultaneous rotation of said rollers includes a bevel gear connected to each of said rollers,

a ring gear coaxial with said aperture meshingly engaging said bevel gears,

and means for rotating said ring gear.

11. A device as recited in claim 9 in which said means ,for simultaneously rotating said rollers includes a bevel gear carried by the outer end of each of said rollers,

a first ring gear meshingly engaging said bevel gears,

said first ring gear being coaxial with said aperture,

a second ring gear coaxial with said first ring gear and coupled thereto,

a rack meshingly engaging said second ring gear,

and means for causing rectilinear movement of said rack for thereby through said second ring gear causing said first ring gear to rotate said bevel gears and hence said rollers.

12. A device :as recited in claim 9 including in addition a link,

means pivotally connecting said rack to said link,

support means pivotally carrying one end of said link,

and means for oscillating the opposite end of said link, whereby said link imparts reciprocative movement to said rack.

13. A device as recited in claim 9 in which said means for controlling the simultaneous rotation of said rollers includes means for continually oscillating said rollers rotationally during the passage of a tube through said aperture.

14. The method of contouring a tube comprising the steps of grasping said tube at either end thereof,

simultaneously rotating said tube and applying a tension force thereto, providing a plurality of rollers cooperating to define an aperture having a contour to be imparted to said tube, said aperture being smaller than the initial diameter of said tube, passing said tube While so rotated and under tension through said aperture so as to deform said tube to the contour of said aperture,

simultaneously with the passing of said tube through said aperture varying the positions of said rollers so as to vary the size of said aperture and the contour to which said tube is deformed,

and simultaneously with so passing said tube applying an oscillatory inwardly directed force on the exterior of said tube.

References (Iited by the Examiner UNITED STATES PATENTS 1,764,598 6/1930 Asbeck -11 1,788,693 1/1931 Stuting 80-56 2,090,535 8/1937 Knoll 80-14 2,686,442 8/1954 Wilson 80-34 2,713,801 7/1955 Singer et a1 80-14.1 2,970,500 2/1961 Appel 78-22 3,019,678 2/1962 Le Fiell 80-14 3,071,992 1/1963 Martin et a1. 80-11 CHARLES W. LANHAM, Primary Examiner. 

1. AN ARRANGEMENT FOR TAPERING TUBES COMPRISING A CLUSTER OF FOUR SUBSTANTIALLY IDENTICAL ROLLERS, EACH ROLLER HAVING A CIRCUMFERENTIAL SIDE WALL CONNECTING TO RADIAL END WALL, SAID ROLLERS BEING POSITIONED WITH THE RADIAL END OF EACH IN JUXTAPOSITION WITH THE CIRCUMFERENTIAL WALL OF THE ADJACENT ROLLER AND THE AXES OF SUCH ADJACENT ROLLERS PERPENDICULAR TO EACH OTHER, THE AXES OF SAID ROLLERS BEING FIXED, EACH ROLLER HAVING A RECESS IN THE PERIPHERAL EDGE AT THE CONNECTION OF SAID SIDE WALL TO SAID END WALL, SAID RECESSES BEING IN ADJACENCY FOR THEREBY DEFINING A CENTRAL OPENING THROUGH SAID CLUSTER OF ROLLERS, AND MEANS FOR PASSING A TUBE THROUGH SAID OPENING FOR CONFORMING SAID TUBE TO THE CONTOUR OF SAID OPENING.
 14. THE METHOD OF CONTOURING A TUBE COMPRISING THE STEPS OF GRASPING SAID TUBE AT EITHER END THEREOF, SIMULTANEOUSLY ROTATING SAID TUBE AND APPLYING A TENSION FORCE THERETO, PROVIDING A PLURALITY ROLLERS COOPERATING TO DEFINE AN APERTURE HAVING A CONTOUR TO BE IMPARTED TO SAID TUBE, SAID APERTURE BEING SMALLER THAN THE INITIAL DIAMETER OF SAID TUBE, PASSING SAID TUBE WHILE SO ROTATED AND UNDER TENSION THROUGH SAID APERTURE SO AS TO DEFORM SAID TUBE TO THE CONTOUR OF SAID APERTURE, SIMULTANEOUSLY WITH SO PASSING SAID TUBE APPLYING SAID APERTURE VARYING THE POSITIONS OF SAID ROLLERS SO AS TO VARY THE SIZE TO SAID APERTURE AND THE CONTOUR TO WHICH SAID TUBE IS DEFORMED, AND SIMULTANEOUSLY WITH SO PASSING SAID TUBE APPLYING AN OSCILLATORY INWARDLY DIRECTED FORCE ON THE EXTERIOR OF SAID TUBE. 